This states that a mutual relationship between two peoples is bettered when there is a satisfactory balance of rewards perceived by each person individually. The more equal the balances are held, the stronger and more permanent the relationship becomes.
It can get into the wrong hands.
1.A hurricane was coming, so everyone boarded up their windows and bought supplies
2.thomas Jefferson was a philosopher with a greath mind:In fact, he invented many devices
3.Robert, carol and tim's friend, is a wonderful cook and he often invites them for brunch
4.the inca people lived in what is now Peru, building machu picchu
5.it's very hot this week,so we're using the air conditiong a lot, even if it is expensive